Appending to JSON file in python

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I want to make a function that recives a data in a type of dictionary, and then appends that data to JSON file. This is how JSON file to looks like [{},{},{}] and after appending I want it to be [{},{},{},{}]. Function below is what I tried, if I use 'w', it overwrites, and if I use 'a', file after appending looks like this [{},{},{}{}] which isn't JSON anymore. How to achieve this?

    def save_to_file(user_data):
        f = open('users.json', 'a')
        json.dump(user_data, f, indent=2)
        f.close()

This is one approach.

Ex:

def save_to_file(user_data):
    with open('users.json') as jfile:
        data = json.loads(jfile)             #Read content
    data.append(user_data)                   #Append 
    with open('users.json', 'w') as jfile:
        json.dump(data, jfile, indent=2)     #Write back

Append to JSON file using Python, A particularly simple one is CSV; which is supported well by python's standard library. The biggest downside is that it only works well for text; it� Python program to append JSON file 1.loads (): . It takes JSON string as a parameter and returns the python dictionary object. 2.update (): . It takes another dictionary as an argument and returns none. 3.dumps (): . It takes a Python object as an argument and returns the JSON string. 4.seek ():

Check the following code: It works:

import json
user_data = {"a":123}
def save_to_file(user_data):
    f = open("tweet.json", 'a')
    json.dump(user_data, f)
    f.close()
save_to_file(user_data)

How to append data to a json file?, Are you overwriting old_data in the second line of your second code fragment? Staff glenn | 5820 posts | PythonAnywhere staff | June 30, 2018, 2:� Then open the destination file, assign the list data inside to a new variable (presumably this will all be valid JSON), then use the 'append' function on this list variable and append the first variable to it. Viola, you have appended to the JSON list. Now just overwrite your destination file with the newly appended list (as JSON).

Rather than writing your own logic perhaps use TinyDB. It uses JSON to save data and makes it rather easy to append/delete data even from multiple sources: https://tinydb.readthedocs.io/en/latest/index.html

appending to json file : Forums : PythonAnywhere, Python simplejson tutorial shows how to read and write JSON data with Python method serializes Python object as a JSON formatted stream to a file object. We call the toJson() method when we add the objects to the list. To handle the data flow in a file, the JSON library in Python uses dump () function to convert the Python objects into their respective JSON object, so it makes easy to write data to files. See the following table given below.

Python simplejson tutorial, In this tutorial, you'll learn how to parse, read, and write JSON to files in Python through examples, using load and dump methods. We'll also cover pretty-printing � with open (DATA_FILENAME, mode = 'a+', encoding = 'utf-8') as feedsjson: feeds = json.load (feedsjson) entry = {} entry [ 'name'] = args.name entry [ 'url'] = args.url json.dump (entry, feeds) Append entry to the file contents if file exists, otherwise append the entry to an empty list and write in in the file:

Reading and Writing JSON to a File in Python, Add these imports at the top of your file: import json import requests. Now, you're going to be working with a list of TODOs cuz like…you know, it's a rite of� You cannot add to the json file. You can collect all the information in memory in a single data structure and dump it to a file. If file already exists from previous runs of the script and you want to add to it, you need to load it first, update in memory and overwrite it.

Working With JSON Data in Python – Real Python, This tutorial will show you how to append to JSON file in Python using simple program. This program uses loads(), dumps(), update() methods. Example 2: Python read JSON file. You can use json.load() method to read a file containing JSON object.. Suppose, you have a file named person.json which contains a JSON object.

Comments
  • So I have to get array of dictionaries from JSON file, then append to that array, then whole array to save in JSON file? It can't be done by appending just one user to the file directly?
  • no issue is still the same, after second appending JSON file looks like {}{} and it should be like {},{}
  • You could also load the JSON and put it into a variable and keep it while you have your script running and when a new dictionary item is needed to append you append it to the variable you have and overwrite your json with the variable. I would not recommend this tho.